Paste from notepad inconsistencies between browsers, formatting issue in IE8

Description

When pasting the attached text file it is correctly displayed in FF/Chrome with the line spacing. In IE the extra spaces are lost. I'm using the default enter mode (paragraph), my CSS file has removed the margin between paragraphs.

p {margin-top: 0px;margin-bottom: 0px;}

In IE, 3 paragraphs are generated. In FF 2 BR tags are inserted in between the sentences. In Chrome DIV blocks are created to maintain formatting. IE is the only browser that loses formatting in this case.

IE (all versions) use <p> tags for patsed text.NOTE: Using no margin for paragraphs

p {margin-top: 0px;margin-bottom: 0px;}

affects only IE because it is the only browser that uses those tags for pasted text.
This is the result of browser inconsistencies, so the part about IE formatting issue should be (at least in my opinion) ignored.

This is caused by the automatons browsers do on pasted data. It's also related to the clipboard interchange feature present in both the browsers and Notepad (or the application used to open the text file).

The fact here is that we can't do anything to solve this problem. The editor receives "post-processed" data, where BRs, DIVs or Ps are already in place. We cannot normalize the data at that point, because we are not able to understand what exactly the source data looked like.